The present invention pertains to secure telecommunications and more particularly to security systems for cellular telecommunications.
The current Secure Telephone market has mainly involved operation over the public switched telephone network using analog phone lines. Currently secure telephone products are made up of many different technologies (Vocoder, modem, Signaling, and Encryption) and consume a fair amount of power.
With the wide spread use of portable communications, battery life is an important consideration. Any additional circuitry in a telecommunication terminal such as a cellular telephone significantly affects the battery life and hence the use of the telephone. Security for speech communications is highly desirable especially for radio telephones in which communications may be readily intercepted. Adding circuitry for security, however, affects the battery life of the radio telephone and hence the radio telephone's ability to be used to transmit and receive.
Battery life is a critical mission parameter for many U.S. government applications(i.e. covert, search and rescue, etc.) which are mandated with the use of secure communications. Commercial applications involving secure communications will have similar requirements which are fundamental to the ergonomics of the radio telephone (i.e. small size, portable, etc.).
Typical security modules for telecommunication terminals include accessory attachments which are placed in series with the device which is to be secured and the target communications medium. Prior art examples include security modules for plain old telephones, fax machines, and secure modems which have been identified in the commercial marketplace.
These typical security systems do not provide for portability and miniaturization. These problems are usually overcome by providing large batteries accompanied by a DC--DC converter to provide the proper power outputs. The packaging of these devices are usually put into a briefcase or a small portable carrying device.